U.S. Sen. Ted Cruz, Facebook CEO Mark Zuckerberg and U.S. Sen. John Cornyn.

The two senators from Texas threw heated hardball questions Thursday at Mark Zuckerberg, the Facebook CEO who is under fire for a massive data breach at his company and how the site may have been used by foreign agents during the 2016 presidential election.

U.S. Sen. John Cornyn asked whether Zuckerberg believed his company bears “some responsibility for the content” on his platform.

“I agree that we’re responsible for the content,” Zuckerberg said.

Zuckerberg promised that in the future, his company would not rely on users to flag objectionable content — like terrorist propaganda — and will instead have artificial intelligence technology to filter such information.

“There are moral and legal obligation questions that I think we’ll have to wrestle with as a society about when we want to require companies to take action proactively on … those things,” Zuckerberg said.

The hearing was a consequence of a New York Times report stating that a data firm called Cambridge Analytica, which did work for Donald Trump’s presidential campaign, exploited a data breach of 50 million Facebook users. Save for testimony a year ago from then-FBI Director James Comey, no hearings have drawn more interest on Capitol Hill in recent years.

During his questioning, Cruz tacked toward a different, earlier controversy, repeatedly asking Zuckberberg if Facebok considers “itself a neutral public forum.” Zuckerberg said the company viewed the site as an open forum for ideas.

“I understand where that concern is coming from because Facebook and the tech industry are located in Silicon Valley, which is an extremely left-leaning place,” Zuckerberg said.

“This is actually a concern that I have, and that I try to root out in the company is making sure that we don’t have any bias in the work that we do, and I think it is a fair concern that people would at least wonder about.”

Cruz then asked if Facebook had taken down any pages from Democratic candidates or liberal groups like Planned Parenthood and MoveOn.org, to which Zuckerberg said he had no knowledge of.

Cruz’s questioning did not touch on Cambridge Analytica, which Cruz hired during his 2016 White House run. Last month, Cruz said the data company assured his campaign at the time that it was operating within legal bounds.

The round of questioning was part of a joint hearing of the U.S. Senate Judiciary and Commerce committees. Both men are members of the Judiciary Committee, and Cruz is also a member of the Commerce Committee.

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